Blue phosphorescent emitters employing functionalized imidazophenthridine and analogues

ABSTRACT

A series of functionalized imidazophenthridine analogue-based blue phosphorescent emitters have been designed, where bulky substituents (e.g., tetrabutyl, phenyl, mesityl, triisopropylbenzene, etc.) are introduced on an imidazophenthridine fragment of the emitters. Bulky substituents may suppress potential excimer formation, as well as improve the solubility of the complexes. This class of emitters may be utilized in luminescent labels, emitters for organic light emitting devices, and lighting applications.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 62/796,275, filed Jan. 24, 2019, which is incorporated by referenceherein in its entirety.

BACKGROUND OF THE INVENTION

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

In recent decades, phosphorescent organic light emitting devices (OLEDs)using palladium (Pd) and platinum (Pt) complexes have attracted greatattention due to their 100% of electron to photon conversion efficiency.However, efficient blue phosphorescent OLEDs with excellent operationalstability remains a significant challenge. Hence, it is in great demandto develop efficient and stable blue phosphorescent emitters.

SUMMARY OF THE INVENTION

According to one embodiment, a compound is provided having Generalformula I, General formula II, General formula III, or General formulaIV;

wherein, in General formula I to IV,

Y^(2a), Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), Y^(5a), Y^(5b),Y^(6a), Y^(6b), Y^(6c), and X² each independently represent C or N;

X, X¹, V¹, and V² each independently represent no bond, O, S, Se, NR⁷,PR⁷, AsR⁷, SbR⁷, BiR⁷, R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸,GeR⁷R⁸, C═O, SO₂, or SeO₂;

each occurrence of R² independently represents substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof;

each of R¹, R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent or presentas a single substituent or multiple substituents, valency permitting,and each of R, R¹, R³, R⁴, R⁵, R⁶, R⁷, and R⁸ independently representsdeuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile,sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof;

each n is independently an integer, valency permitting; and

L⁴, L⁵, and L⁶ each independently represents a 5- to 10-membered aryl,heteroaryl, fused aryl, or fused heteroaryl.

According to another embodiment, an organic light emitting device (OLED)is provided. The OLED can include an anode; a cathode; and an organiclayer disposed between the anode and the cathode. The organic layer caninclude a compound of General formula I, General formula II, Generalformula III, or General Formula IV. The OLED can be incorporated into aconsumer product.

According to another embodiment, a formulation is provided. Theformulation can include a compound of General formula I, General formulaII, General formula III, or General Formula IV.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of preferred embodiments will bebetter understood when read in conjunction with the appended drawings.For the purpose of illustration, there are shown in the drawingsembodiments which are presently preferred. It should be understood,however, that the disclosure is not limited to the precise arrangementsand instrumentalities of the embodiments shown in the drawings.

FIG. 1 is a schematic diagram of an organic light emitting device.

FIG. 2 is a plot of the emission spectrum of PtON2-PP4 in methylenechloride at room temperature.

FIG. 3 is a plot of the emission spectrum of Pt2O2-PPy5-tb3 in methylenechloride at room temperature.

FIG. 4 is a plot of the emission spectrum of Pt2O2-P2-M3 at roomtemperature and at 77 K.

FIG. 5 depicts the results of DFT modeling of Pt202-P2 and Pt2O2-P2-M3.

DETAILED DESCRIPTION

The present disclosure relates in part to the unexpected discovery thatphosphorescent emitters with imidazophenthridines having bulkysubstituents have lower propensity to form excimers and also haveimproved solubility.

Definitions

It is to be understood that the figures and descriptions herein havebeen simplified to illustrate elements that are relevant for a clearunderstanding of the present disclosure, while eliminating, for thepurpose of clarity, many other elements found in the art related tophosphorescent organic light emitting devices and the like. Those ofordinary skill in the art may recognize that other elements and/or stepsare desirable and/or required in implementing the devices disclosedherein. However, because such elements and steps are well known in theart, a discussion of such elements and steps is not provided herein. Thedisclosure herein is directed to all such variations and modificationsto such elements and methods known to those skilled in the art.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure pertains. Although any methods,materials and components similar or equivalent to those described hereincan be used in the practice or testing of the disclosed devices andcompositions, the preferred methods, and materials are described.

As used herein, each of the following terms has the meaning associatedwith it in this section.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

“About” as used herein when referring to a measurable value such as anamount, a temporal duration, and the like, is meant to encompassvariations of ±20%, ±10%, ±5%, ±1%, or ±0.1% from the specified value,as such variations are appropriate.

Throughout this disclosure, various aspects can be presented in a rangeformat. It should be understood that the description in range format ismerely for convenience and brevity and should not be construed as aninflexible limitation. Accordingly, the description of a range should beconsidered to have specifically disclosed all the possible subranges aswell as individual numerical values within that range. For example,description of a range such as from 1 to 6 should be considered to havespecifically disclosed subranges such as from 1 to 3, from 1 to 4, from1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well asindividual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5,5.3, 6 and any whole and partial increments therebetween. This appliesregardless of the breadth of the range.

Disclosed are the components to be used to prepare the compositions ofthe disclosure as well as the compositions themselves to be used withinthe methods disclosed herein. These and other materials are disclosedherein, and it is understood that when combinations, subsets,interactions, groups, etc. of these materials are disclosed that whilespecific reference of each various individual and collectivecombinations and permutation of these compounds cannot be explicitlydisclosed, each is specifically contemplated and described herein. Forexample, if a particular compound is disclosed and discussed and anumber of modifications that can be made to a number of moleculesincluding the compounds are discussed, specifically contemplated is eachand every combination and permutation of the compound and themodifications that are possible unless specifically indicated to thecontrary. Thus, if a class of molecules A, B, and C are disclosed aswell as a class of molecules D, E, and F and an example of a combinationmolecule, A-D is disclosed, then even if each is not individuallyrecited each is individually and collectively contemplated meaningcombinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considereddisclosed. Likewise, any subset or combination of these is alsodisclosed. Thus, for example, the sub-group of A-E, B-F, and C-E wouldbe considered disclosed. This concept applies to all aspects of thisapplication including, but not limited to, steps in methods of makingand using the compositions disclosed herein. Thus, if there are avariety of additional steps that can be performed it is understood thateach of these additional steps can be performed with any specificembodiment or combination of embodiments of the methods disclosedherein.

As referred to herein, a linking atom or a linking group can connect twogroups such as, for example, an N and C group. The linking atom canoptionally, if valency permits, have other chemical moieties attached.For example, in one aspect, an oxygen would not have any other chemicalgroups attached as the valency is satisfied once it is bonded to twogroups (e.g., N and/or C groups). In another aspect, when carbon is thelinking atom, two additional chemical moieties can be attached to thecarbon. Suitable chemical moieties include, but are not limited to,hydrogen, hydroxyl, alkyl, alkoxy, ═O, halogen, nitro, amine, amide,thiol, aryl, heteroaryl, cycloalkyl, and heterocyclyl.

The term “cyclic structure” or the like terms used herein refer to anycyclic chemical structure which includes, but is not limited to, aryl,heteroaryl, cycloalkyl, cycloalkenyl, and heterocyclyl.

As used herein, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a broad aspect, thepermissible substituents include acyclic and cyclic, branched andunbranched, carbocyclic and heterocyclic, and aromatic and nonaromaticsubstituents of organic compounds. Illustrative substituents include,for example, those described below. The permissible substituents can beone or more and the same or different for appropriate organic compounds.For purposes of this disclosure, the heteroatoms, such as nitrogen, canhave hydrogen substituents and/or any permissible substituents oforganic compounds described herein which satisfy the valences of theheteroatoms. This disclosure is not intended to be limited in any mannerby the permissible substituents of organic compounds. Also, the terms“substitution” or “substituted with” include the implicit proviso thatsuch substitution is in accordance with permitted valence of thesubstituted atom and the substituent, and that the substitution resultsin a stable compound, e.g., a compound that does not spontaneouslyundergo transformation such as by rearrangement, cyclization,elimination, etc. It is also contemplated that, in certain aspects,unless expressly indicated to the contrary, individual substituents canbe further optionally substituted (i.e., further substituted orunsubstituted).

The term “alkyl” as used herein is a branched or unbranched saturatedhydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl,isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl,dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. Thealkyl group can be cyclic or acyclic. The alkyl group can be branched orunbranched. The alkyl group can also be substituted or unsubstituted.For example, the alkyl group can be substituted with one or more groupsincluding, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether,halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol, as described herein.A “lower alkyl” group is an alkyl group containing from one to six(e.g., from one to four) carbon atoms.

Throughout the specification “alkyl” is generally used to refer to bothunsubstituted alkyl groups and substituted alkyl groups, however,substituted alkyl groups are also specifically referred to herein byidentifying the specific substituent(s) on the alkyl group. For example,the term “halogenated alkyl” or “haloalkyl” specifically refers to analkyl group that is substituted with one or more halide, e.g., fluorine,chlorine, bromine, or iodine. The term “alkoxyalkyl” specifically refersto an alkyl group that is substituted with one or more alkoxy groups, asdescribed below. The term “alkylamino” specifically refers to an alkylgroup that is substituted with one or more amino groups, as describedbelow, and the like. When “alkyl” is used in one instance and a specificterm such as “alkylalcohol” is used in another, it is not meant to implythat the term “alkyl” does not also refer to specific terms such as“alkylalcohol” and the like.

This practice is also used for other groups described herein. That is,while a term such as “cycloalkyl” refers to both unsubstituted andsubstituted cycloalkyl moieties, the substituted moieties can, inaddition, be specifically identified herein; for example, a particularsubstituted cycloalkyl can be referred to as, e.g., an“alkylcycloalkyl.” Similarly, a substituted alkoxy can be specificallyreferred to as, e.g., a “halogenated alkoxy,” a particular substitutedalkenyl can be, e.g., an “alkenylalcohol,” and the like. Again, thepractice of using a general term, such as “cycloalkyl,” and a specificterm, such as “alkylcycloalkyl,” is not meant to imply that the generalterm does not also include the specific term.

The term “cycloalkyl” as used herein is a non-aromatic carbon-based ringcomposed of at least three carbon atoms. Examples of cycloalkyl groupsinclude, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, norbornyl, and the like. The term “heterocycloalkyl” is atype of cycloalkyl group as defined above, and is included within themeaning of the term “cycloalkyl,” where at least one of the carbon atomsof the ring is replaced with a heteroatom such as, but not limited to,nitrogen, oxygen, sulfur, or phosphorus. The cycloalkyl group andheterocycloalkyl group can be substituted or unsubstituted. Thecycloalkyl group and heterocycloalkyl group can be substituted with oneor more groups including, but not limited to, alkyl, cycloalkyl, alkoxy,amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol asdescribed herein.

The term “polyalkylene group” as used herein is a group having two ormore CH₂ groups linked to one another. The polyalkylene group can berepresented by the formula —(CH₂)_(a)—, where “a” is an integer of from2 to 500.

The terms “alkoxy” and “alkoxyl” as used herein to refer to an alkyl orcycloalkyl group bonded through an ether linkage; that is, an “alkoxy”group can be defined as —OA¹ where A¹ is alkyl or cycloalkyl as definedabove. “Alkoxy” also includes polymers of alkoxy groups as justdescribed; that is, an alkoxy can be a polyether such as —OA¹-OA² or—OA¹-(OA²)_(a)-OA³, where “a” is an integer of from 1 to 200 and A¹, A²,and A³ are alkyl and/or cycloalkyl groups.

The term “alkenyl” as used herein is a hydrocarbon group of from 2 to 24carbon atoms with a structural formula containing at least onecarbon-carbon double bond. Asymmetric structures such as (A¹A²)C═C(A³A⁴)are intended to include both the E and Z isomers. This can be presumedin structural formulae herein wherein an asymmetric alkene is present,or it can be explicitly indicated by the bond symbol C═C. The alkenylgroup can be substituted with one or more groups including, but notlimited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl,cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester,ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, orthiol, as described herein.

The term “cycloalkenyl” as used herein is a non-aromatic carbon-basedring composed of at least three carbon atoms and containing at least onecarbon-carbon double bond, i.e., C═C. Examples of cycloalkenyl groupsinclude, but are not limited to, cyclopropenyl, cyclobutenyl,cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl,norbornenyl, and the like. The term “heterocycloalkenyl” is a type ofcycloalkenyl group as defined above, and is included within the meaningof the term “cycloalkenyl,” where at least one of the carbon atoms ofthe ring is replaced with a heteroatom such as, but not limited to,nitrogen, oxygen, sulfur, or phosphorus. The cycloalkenyl group andheterocycloalkenyl group can be substituted or unsubstituted. Thecycloalkenyl group and heterocycloalkenyl group can be substituted withone or more groups including, but not limited to, alkyl, cycloalkyl,alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone,azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “alkynyl” as used herein is a hydrocarbon group of 2 to 24carbon atoms with a structural formula containing at least onecarbon-carbon triple bond. The alkynyl group can be unsubstituted orsubstituted with one or more groups including, but not limited to,alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether,halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, asdescribed herein.

The term “cycloalkynyl” as used herein is a non-aromatic carbon-basedring composed of at least seven carbon atoms and containing at least onecarbon-carbon triple bound. Examples of cycloalkynyl groups include, butare not limited to, cycloheptynyl, cyclooctynyl, cyclononynyl, and thelike. The term “heterocycloalkynyl” is a type of cycloalkenyl group asdefined above, and is included within the meaning of the term“cycloalkynyl,” where at least one of the carbon atoms of the ring isreplaced with a heteroatom such as, but not limited to, nitrogen,oxygen, sulfur, or phosphorus. The cycloalkynyl group andheterocycloalkynyl group can be substituted or unsubstituted. Thecycloalkynyl group and heterocycloalkynyl group can be substituted withone or more groups including, but not limited to, alkyl, cycloalkyl,alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone,azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “aryl” as used herein is a group that contains any carbon-basedaromatic group including, but not limited to, benzene, naphthalene,phenyl, biphenyl, phenoxybenzene, and the like. The term “aryl” alsoincludes “heteroaryl,” which is defined as a group that contains anaromatic group that has at least one heteroatom incorporated within thering of the aromatic group. Examples of heteroatoms include, but are notlimited to, nitrogen, oxygen, sulfur, and phosphorus. Likewise, the term“non-heteroaryl,” which is also included in the term “aryl,” defines agroup that contains an aromatic group that does not contain aheteroatom. The aryl group can be substituted or unsubstituted. The arylgroup can be substituted with one or more groups including, but notlimited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl,cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester,ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiolas described herein. The term “biaryl” is a specific type of aryl groupand is included in the definition of “aryl.” Biaryl refers to two arylgroups that are bound together via a fused ring structure, as innaphthalene, or are attached via one or more carbon-carbon bonds, as inbiphenyl.

The term “aldehyde” as used herein is represented by the formula —C(O)H.Throughout this specification “C(O)” is a short hand notation for acarbonyl group, i.e., C═O.

The terms “amine” or “amino” as used herein are represented by theformula —NA¹A², where A¹ and A² can be, independently, hydrogen oralkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl,or heteroaryl group as described herein.

The term “alkylamino” as used herein is represented by the formula—NH(-alkyl) where alkyl is a described herein. Representative examplesinclude, but are not limited to, methylamino group, ethylamino group,propylamino group, isopropylamino group, butylamino group, isobutylaminogroup, (sec-butyl)amino group, (tert-butyl)amino group, pentylaminogroup, isopentylamino group, (tert-pentyl)amino group, hexylamino group,and the like.

The term “dialkylamino” as used herein is represented by the formula—N(-alkyl)₂ where alkyl is a described herein. Representative examplesinclude, but are not limited to, dimethylamino group, diethylaminogroup, dipropylamino group, diisopropylamino group, dibutylamino group,diisobutylamino group, di(sec-butyl)amino group, di(tert-butyl)aminogroup, dipentylamino group, diisopentylamino group, di(tert-pentyl)aminogroup, dihexylamino group, N-ethyl-N-methylamino group,N-methyl-N-propylamino group, N-ethyl-N-propylamino group and the like.

The term “carboxylic acid” as used herein is represented by the formula—C(O)OH.

The term “ester” as used herein is represented by the formula —OC(O)A¹or —C(O)OA¹, where A¹ can be alkyl, cycloalkyl, alkenyl, cycloalkenyl,alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.The term “polyester” as used herein is represented by the formula-(A¹O(O)C-A²-C(O)O), or -(A¹O(O)C-A²-OC(O))_(a)—, where A¹ and A² canbe, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl,cycloalkynyl, aryl, or heteroaryl group described herein and “a” is aninteger from 1 to 500. “Polyester” is as the term used to describe agroup that is produced by the reaction between a compound having atleast two carboxylic acid groups with a compound having at least twohydroxyl groups.

The term “ether” as used herein is represented by the formula A¹OA²,where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group describedherein. The term “polyether” as used herein is represented by theformula -(A¹O-A²O)_(a)—, where A¹ and A² can be, independently, analkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl,or heteroaryl group described herein and “a” is an integer of from 1 to500. Examples of polyether groups include polyethylene oxide,polypropylene oxide, and polybutylene oxide.

The term “halide” as used herein refers to the halogens fluorine,chlorine, bromine, and iodine.

The term “heterocyclyl,” as used herein refers to single andmulti-cyclic non-aromatic ring systems and “heteroaryl” as used hereinrefers to single and multi-cyclic aromatic ring systems: in which atleast one of the ring members is other than carbon. The term“heterocyclyl” includes azetidine, dioxane, furan, imidazole,isothiazole, isoxazole, morpholine, oxazole, oxazole, including,1,2,3-oxadiazole, 1,2,5-oxadiazole and 1,3,4-oxadiazole, piperazine,piperidine, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine,pyrrole, pyrrolidine, tetrahydrofuran, tetrahydropyran, tetrazine,including 1,2,4,5-tetrazine, tetrazole, including 1,2,3,4-tetrazole and1,2,4,5-tetrazole, thiadiazole, including, 1,2,3-thiadiazole,1,2,5-thiadiazole, and 1,3,4-thiadiazole, thiazole, thiophene, triazine,including 1,3,5-triazine and 1,2,4-triazine, triazole, including,1,2,3-triazole, 1,3,4-triazole, and the like.

The term “hydroxyl” as used herein is represented by the formula —OH.

The term “ketone” as used herein is represented by the formula A¹C(O)A²,where A¹ and A² can be, independently, an alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group asdescribed herein.

The term “azide” as used herein is represented by the formula —N₃.

The term “nitro” as used herein is represented by the formula —NO₂.

The term “nitrile” as used herein is represented by the formula —CN.

The term “ureido” as used herein refers to a urea group of the formula—NHC(O)NH₂ or —NHC(O)NH—.

The term “phosphoramide” as used herein refers to a group of the formula—P(O)(NA¹A²)₂, where A¹ and A² can be, independently, hydrogen or analkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, or heteroaryl group as described herein.

The term “carbamoyl” as used herein refers to an amide group of theformula —CONA¹A², where A¹ and A² can be, independently, hydrogen or analkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, or heteroaryl group as described herein.

The term “sulfamoyl” as used herein refers to a group of the formula—S(O)₂NA¹A², where A¹ and A² can be, independently, hydrogen or analkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, or heteroaryl group as described herein.

The term “silyl” as used herein is represented by the formula —SiA1A²A³, where A¹, A², and A¹ can be, independently, hydrogen or an alkyl,cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl,or heteroaryl group as described herein.

The term “sulfo-oxo” as used herein is represented by the formulas—S(O)A¹, —S(O)₂A¹, —OS(O)₂A¹, or —OS(O)₂OA¹, where A¹ is hydrogen or analkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl,or heteroaryl group as described herein. Throughout this specification“S(O)” is a short hand notation for S═O. The term “sulfonyl” is usedherein to refer to the sulfo-oxo group represented by the formula—S(O)₂A¹, where A^(t) is hydrogen or an alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group asdescribed herein. The term “sulfone” as used herein is represented bythe formula A'S(O)₂A², where A¹ and A² can be, independently, an alkyl,cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, orheteroaryl group as described herein. The term “sulfoxide” as usedherein is represented by the formula A'S(O)A², where A¹ and A² can be,independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl,cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “thiol” as used herein is represented by the formula —SH.

“R,” “R¹,” “R²,” “R³,” “R^(n),” where n is an integer, as used hereincan, independently, include hydrogen or one or more of the groups listedabove. For example, if R¹ is a straight chain alkyl group, one of thehydrogen atoms of the alkyl group can optionally be substituted with ahydroxyl group, an alkoxy group, an alkyl group, a halide, and the like.Depending upon the groups that are selected, a first group can beincorporated within a second group or, alternatively, the first groupcan be pendant (i.e., attached) to the second group. For example, withthe phrase “an alkyl group comprising an amino group,” the amino groupcan be incorporated within the backbone of the alkyl group.Alternatively, the amino group can be attached to the backbone of thealkyl group. The nature of the group(s) that is (are) selected willdetermine if the first group is embedded or attached to the secondgroup.

As described herein, compounds of the disclosure may contain “optionallysubstituted” moieties. In general, the term “substituted,” whetherpreceded by the term “optionally” or not, means that one or morehydrogens of the designated moiety are replaced with a suitablesubstituent. Unless otherwise indicated, an “optionally substituted”group may have a suitable substituent at each substitutable position ofthe group, and when more than one position in any given structure may besubstituted with more than one substituent selected from a specifiedgroup, the substituent may be either the same or different at everyposition. Combinations of substituents envisioned by this disclosure arepreferably those that result in the formation of stable or chemicallyfeasible compounds. It is also contemplated that, in certain aspects,unless expressly indicated to the contrary, individual substituents canbe further optionally substituted (i.e., further substituted orunsubstituted).

In some aspects, a structure of a compound can be represented by aformula:

which is understood to be equivalent to a formula:

wherein n is typically an integer. That is, R^(n) is understood torepresent five independent substituents, R^(n(a)), R^(n(b)), R^(n(c)),R^(n(d)), R^(n(e)). By “independent substituents,” it is meant that eachR substituent can be independently defined. For example, if in oneinstance R^(n(a)) is halogen, then R^(n(b)) is not necessarily halogenin that instance.

Several references to R, R¹, R², R³, R⁴, R⁵, R⁶, etc. are made inchemical structures and moieties disclosed and described herein. Anydescription of R, R¹, R², R³, R⁴, R⁵, R⁶, etc. in the specification isapplicable to any structure or moiety reciting R, R¹, R², R³, R⁴, R⁵,R⁶, etc. respectively.

Compounds

Owing to the potential of phosphorescent tetradentate platinum complexesfor harvesting both electro-generated singlet and triplet excitions toachieve 100% internal quantum efficiency, these complexes are goodcandidate for the emitting materials of OLEDs. In some cases, there isan “emitting portion” and an “ancillary portion” in a ligand of platinumcomplex (e.g., a tetradentate platinum complex). If stabilizingsubstitution(s), such as conjugated group(s), aryl or heteroaromaticsubstitution(s) and so on, were introduced into the emitting portion,the “Highest Occupied Molecular Orbital” (HOMO) energy level, the“Lowest Unoccupied Molecular Orbital” (LUMO) energy level, or both maybe changed. So the energy gap between the HOMO and LUMO can be tuned.Thus, the emission spectra of phosphorescent tetradentate platinumcomplexes can be modified to lesser or greater extents, such that theemission spectra can become narrower or broader, such that the emissionspectra can exhibit a blue shift or a red shift, or a combinationthereof.

The emission of such disclosed complexes can be tuned, for example, fromthe ultraviolet to near-infrared, by, for example, modifying the ligandstructure. In another aspect, the disclosed complexes can provideemission over a majority of the visible spectrum. In a specific example,the disclosed complexes can emit light over a range of from about 400 nmto about 700 nm. In another aspect, the disclosed complexes haveimproved stability and efficiency over traditional emission complexes.In yet another aspect, the disclosed complexes can be useful asluminescent labels in, for example, bio-applications, anti-canceragents, emitters in organic light emitting devices (OLED), or acombination thereof. In another aspect, the disclosed complexes can beuseful in light emitting devices, such as, for example, compactfluorescent lamps (CFL), light emitting diodes (LED), incandescentlamps, and combinations thereof.

A series of functionalized imidazophenthridine and analogues based bluephosphorescent emitters have been designed, where bulky substituents(R²)_(n) (e.g. tetrabutyl, phenyl, mesityl, triisopropylbenzene, etc.)are chosen to introduce on imidazophenthridine fragment of the emitters.While not wishing to be bound by any particular scientific theory, thereare two main purposes for introducing bulky substituents: first, thebulky substituents can suppress the planarity of the complexes toeliminate the potential excimer formation; second, the substituents canas well as improve the solubility of the complexes. This class ofemitters could be utilized in, for example, full color displays andlighting applications.

The compounds can also have other known emission mechanisms which areuseful in devices.

Disclosed herein are compounds or compound complexes comprising platinumand/or palladium. The terms compound, complex, or combinations thereof,are used interchangeably herein. In one aspect, the compounds disclosedherein have a neutral charge.

The compounds disclosed herein can exhibit desirable properties and haveemission spectra, absorption spectra, or both that can be tuned via theselection of appropriate ligands. In another aspect, the presentdisclosure can exclude any one or more of the compounds, structures, orportions thereof, specifically recited herein.

The compounds disclosed herein are suited for use in a wide variety ofoptical and electro-optical devices, including, but not limited to,photo-absorbing devices such as solar- and photo-sensitive devices,organic light emitting devices (OLEDs), photo-emitting devices, ordevices capable of both photo-absorption and emission and as markers forbio-applications.

As briefly described above, the disclosed compounds are platinum and/orpalladium complexes. In one aspect, the compounds disclosed herein canbe used as host materials for OLED applications, such as full colordisplays.

The compounds disclosed herein are useful in a variety of applications.As light emitting materials, the compounds can be useful in organiclight emitting devices (OLEDs), luminescent devices and displays, andother light emitting devices.

In another aspect, the compounds can provide improved efficiency,improved operational lifetimes, or both in lighting devices, such as,for example, organic light emitting devices, as compared to conventionalmaterials.

The compounds of the disclosure can be made using a variety of methods,including, but not limited to those recited in the examples providedherein.

Compounds

In one aspect, the present disclosure relates to compounds of Generalformula I, General formula II, General formula III, or General formulaIV:

wherein, in General formula I to IV,

Y^(2a), Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), Y^(5a), Y^(5b),Y^(6a), Y^(6b), Y^(6c), and X² each independently represent C or N;

X, X¹, V¹, and V² each independently represent no bond, O, S, Se, NR⁷,PR⁷, AsR⁷, SbR⁷, BiR⁷, R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸,GeR⁷R⁸, C═O, SO₂, or SeO₂;

each occurrence of R² independently represents substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof;

each of R, R¹, R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent orpresent as a single substituent or multiple substituents, valencypermitting, and each of R, R¹, R³, R⁴, R⁵, R⁶, R⁷, and R⁸ independentlyrepresents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile,isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substitutedor unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl,heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino,dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl,aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino,aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio,ureido, phosphoramide, silyl, polymeric; or any conjugate or combinationthereof;

each n is independently an integer, valency permitting; and

L⁴, L⁵, and L⁶ each independently represents a 5- to 10-membered aryl,heteroaryl, fused aryl, or fused heteroaryl.

In one embodiment, the compound of General formula I, General formulaII, General formula III, or General formula IV, is a compound of Generalformula V, General formula VI, General formula VII, or General formulaVIII:

wherein, in General formula V to VIII;

Y²a Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), Y^(4d) and X² eachindependently represents C or N;

each of X and X¹ independently represents no bond, O, S, Se, NR⁷, PR⁷,AsR⁷, SbR⁷, BiR⁷, R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸,GeR⁷R⁸, C═O, SO₂, or SeO₂;

each of R, R¹, R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent orpresent as a single substituent or multiple substituents, valencypermitting, and each of R, R¹, R³, R⁴, R⁵, R⁶, R and R⁸ independentlyrepresents deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile,isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substitutedor unsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl,heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino,dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl,aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino,aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio,ureido, phosphoramide, silyl, polymeric; or any conjugate or combinationthereof; and

each n is independently an integer, valency permitting.

In one embodiment, the compound has a neutral charge.

In one embodiment, X and X¹ are present or not present. In oneembodiment, when X or X¹ is not present, then that variable representsno bond. In one embodiment, X and X¹ are both present. In oneembodiment, neither of X¹ and X² represent no bond. In one embodiment, Xand X¹ each independently represent O, NR⁷, CR⁷R⁸, or SiR⁷R⁸. In oneembodiment, X² represents N. In one embodiment, at least one of Y^(2a),Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), and Y^(4d) represents N.In one embodiment, only one of Y^(2a), Y^(2b), Y²c, Y^(2d), Y^(4a),Y^(4b), Y^(4c), and Y^(4d) represents N and the remaining of Y^(2a)Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), and Y^(4d) represent C.

In one embodiment, L⁶ is 5- to 10-membered heteroaryl or fusedheteroaryl. In one embodiment, L⁶ is imidazole, benzimidazole, orpyridine.

In one embodiment, V¹ and V² are present or not present. In oneembodiment, when V¹ or V² is not present, then that variable representsno bond. In one embodiment, at least one of V¹ and V² represents nobond. In one embodiment, at least one of V¹ and V² is not present.

In one embodiment, each occurrence of R² is independently selected fromthe group consisting of substituted or unsubstituted alkyl, substitutedor unsubstituted aryl, or combinations thereof. In one embodiment, atleast one occurrence of R⁵ is selected from the group consisting ofsubstituted or unsubstituted alkyl, substituted or unsubstituted aryl,or combinations thereof.

In one embodiment, each occurrence of R² is independently selected fromthe group consisting of the following:

Exemplary substituents R¹ and R³ to R⁸ include, but are not limited to,the following:

wherein each of R independently represents hydrogen, deuterium, halogen,hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto,sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl,cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl,alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino,diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl,acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino,sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl,polymeric; or any conjugate or combination thereof.

Exemplary complexes of General formula I to VIII include, but are notlimited to, the following complexes:

Compositions and Devices

Also disclosed herein are devices comprising one or more compound and/orcompositions disclosed herein.

In one aspect, the device is an electro-optical device. Electro-opticaldevices include, but are not limited to, photo-absorbing devices such assolar- and photo-sensitive devices, organic light emitting devices(OLEDs), photo-emitting devices, or devices capable of bothphoto-absorption and emission and as markers for bio-applications. Forexample, the device can be an OLED.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art. Such devices are disclosed herein which comprise oneor more of the compounds or compositions disclosed herein.

OLEDs can be produced by methods known to those skilled in the art. Ingeneral, the OLED is produced by successive vapor deposition of theindividual layers onto a suitable substrate. Suitable substratesinclude, for example, glass, inorganic materials such as ITO or IZO orpolymer films. For the vapor deposition, customary techniques may beused, such as thermal evaporation, chemical vapor deposition (CVD),physical vapor deposition (PVD) and others.

In an alternative process, the organic layers may be coated fromsolutions or dispersions in suitable solvents, in which case coatingtechniques known to those skilled in the art are employed. Suitablecoating techniques are, for example, spin-coating, the casting method,the Langmuir-Blodgett (“LB”) method, the inkjet printing method,dip-coating, letterpress printing, screen printing, doctor bladeprinting, slit-coating, roller printing, reverse roller printing, offsetlithography printing, flexographic printing, web printing, spraycoating, coating by a brush or pad printing, and the like. Among theprocesses mentioned, in addition to the aforementioned vapor deposition,preference is given to spin-coating, the inkjet printing method and thecasting method since they are particularly simple and inexpensive toperform. In the case that layers of the OLED are obtained by thespin-coating method, the casting method or the inkjet printing method,the coating can be obtained using a solution prepared by dissolving thecomposition in a concentration of 0.0001 to 90% by weight in a suitableorganic solvent such as benzene, toluene, xylene, tetrahydrofuran,methyltetrahydrofuran, N,N-dimethylformamide, acetone, acetonitrile,anisole, dichloromethane, dimethyl sulfoxide, water and mixturesthereof.

Compounds described herein can be used in a light emitting device suchas an OLED. FIG. 1 depicts a cross-sectional view of an OLED 100. OLED100 includes substrate 102, anode 104, hole-transporting material(s)(HTL) 106, light processing material 108, electron-transportingmaterial(s) (ETL) 110, and a metal cathode layer 112. Anode 104 istypically a transparent material, such as indium tin oxide. Lightprocessing material 108 may be an emissive material (EML) including anemitter and a host.

In various aspects, any of the one or more layers depicted in FIG. 1 mayinclude indium tin oxide (ITO), poly(3,4-ethylenedioxythiophene)(PEDOT), polystyrene sulfonate (PSS),N,N′-di-1-naphthyl-N,N-diphenyl-1,1′-biphenyl-4,4′ diamine (NPD),1,1-bis((di-4-tolylamino)phenyl)cyclohexane (TAPC),2,6-Bis(N-carbazolyl)pyridine (mCpy),2,8-bis(diphenylphosphoryl)dibenzothiophene (PO15), LiF, Al, or acombination thereof.

Light processing material 108 may include one or more compounds of thepresent disclosure optionally together with a host material. The hostmaterial can be any suitable host material known in the art. Theemission color of an OLED is determined by the emission energy (opticalenergy gap) of the light processing material 108, which can be tuned bytuning the electronic structure of the emitting compounds, the hostmaterial, or both. Both the hole-transporting material in the HTL layer106 and the electron-transporting material(s) in the ETL layer 110 mayinclude any suitable hole-transporter known in the art.

Compounds described herein may exhibit phosphorescence. PhosphorescentOLEDs (i.e., OLEDs with phosphorescent emitters) typically have higherdevice efficiencies than other OLEDs, such as fluorescent OLEDs. Lightemitting devices based on electrophosphorescent emitters are describedin more detail in WO2000/070655 to Baldo et al., which is incorporatedherein by this reference for its teaching of OLEDs, and in particularphosphorescent OLEDs.

As contemplated herein, an OLED may include an anode, a cathode, and anorganic layer disposed between the anode and the cathode. The organiclayer may include a host and a phosphorescent dopant. The organic layercan include a compound disclosed herein and its variations as describedherein.

In some embodiments, the OLED has one or more characteristics selectedfrom the group consisting of being flexible, being rollable, beingfoldable, being stretchable, and being curved. In some embodiments, theOLED is transparent or semi-transparent. In some embodiments, the OLEDfurther comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising adelayed fluorescent emitter. In some embodiments, the OLED comprises aRGB pixel arrangement or white plus color filter pixel arrangement. Insome embodiments, the OLED is a mobile device, a hand held device, or awearable device. In some embodiments, the OLED is a display panel havingless than 10 inch diagonal or 50 square inch area. In some embodiments,the OLED is a display panel having at least 10 inch diagonal or 50square inch area. In some embodiments, the OLED is a lighting panel.

In one embodiment, the consumer product is selected from the groupconsisting of a flat panel display, a computer monitor, a medicalmonitor, a television, a billboard, a light for interior or exteriorillumination and/or signaling, a heads-up display, a fully or partiallytransparent display, a flexible display, a laser printer, a telephone, acell phone, tablet, a phablet, a personal digital assistant (PDA), awearable device, a laptop computer, a digital camera, a camcorder, aviewfinder, a micro-display that is less than 2 inches diagonal, a 3-Ddisplay, a virtual reality or augmented reality display, a vehicle, avideo wall comprising multiple displays tiled together, a theater orstadium screen, and a sign.

In some embodiments of the emissive region, the emissive region furthercomprises a host, wherein the host comprises at least one selected fromthe group consisting of metal complex, triphenylene, carbazole,dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-triphenylene,aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, andaza-dibenzoselenophene.

The organic layer can also include a host. In some embodiments, two ormore hosts are preferred. In some embodiments, the hosts used maybe a)bipolar, b) electron transporting, c) hole transporting or d) wide bandgap materials that play little role in charge transport. In someembodiments, the host can include a metal complex. The host can be atriphenylene containing benzo-fused thiophene or benzo-fused furan. Anysubstituent in the host can be an unfused substituent independentlyselected from the group consisting of CnH2n+1, OCnH2n+1, OAr1,N(CnH2n+1)₂, N(Ar1)(Ar2), CH═CH-CnH2n+1, C≡C-CnH2n+1, Ar1, Ar1-Ar2, andCnH2n-Ar1, or the host has no substitutions. In the precedingsubstituents n can range from 1 to 10; and Ar1 and Ar2 can beindependently selected from the group consisting of benzene, biphenyl,naphthalene, triphenylene, carbazole, and heteroaromatic analogsthereof. The host can be an inorganic compound. For example, a Zncontaining inorganic material e.g. ZnS.

Suitable hosts may include, but are not limited to, mCP(1,3-bis(carbazol-9-yl)benzene), mCPy (2,6-bis(N-carbazolyl)pyridine),TCP (1,3,5-tris(carbazol-9-yl)benzene), TCTA(4,4′,4″-tris(carbazol-9-yl)triphenylamine), TPBi(1,3,5-tris(-phenyl-1-H-benzimidazol-2-yl)benzene), mCBP(3,3-di(9H-carbazol-9-yl)biphenyl), pCBP(4,4′-bis(carbazol-9-yl)biphenyl), CDBP(4,4′-bis(9-carbazolyl)-2,2′-dimethylbiphenyl), DMFL-CBP(4,4′-bis(carbazol-9-yl)-9,9-dimethylfluorene), FL-4CBP(4,4′-bis(carbazol-9-yl)-9,9-bis(9-phenyl-9H-carbazole)fluorene),FL-2CBP (9,9-bis(4-carbazol-9-yl)phenyl)fluorene, also abbreviated asCPF), DPFL-CBP (4,4′-bis(carbazol-9-yl)-9,9-ditolylfluorene), FL-2CBP(9,9-bis(9-phenyl-9H-carbazole)fluorene), Spiro-CBP(2,2′,7,7′-tetrakis(carbazol-9-yl)-9,9′-spirobifluorene), ADN(9,10-di(naphth-2-yl)anthracene), TBADN(3-tert-butyl-9,10-di(naphth-2-yl)anthracene), DPVBi(4,4′-bis(2,2-diphenylethen-1-yl)-4,4′-dimethylphenyl), p-DMDPVBi(4,4′-bis(2,2-diphenylethen-1-yl)-4,4′-dimethylphenyl), TDAF(tert(9,9-diarylfluorene)), BSBF(2-(9,9′-spirobifluoren-2-yl)-9,9′-spirobifluorene), TSBF(2,7-bis(9,9′-spirobifluoren-2-yl)-9,9′-spirobifluorene), BDAF(bis(9,9-diarylfluorene)), p-TDPVBi(4,4′-bis(2,2-diphenylethen-1-yl)-4,4′-di-(tert-butyl)phenyl), TPB3(1,3,5-tri(pyren-1-yl)benzene, PBD(2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), BP-OXD-Bpy(6,6′-bis[5-(biphenyl-4-yl)-1,3,4-oxadiazo-2-yl]-2,2′-bipyridyl), NTAZ(4-(naphth-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), Bpy-OXD(1,3-bis[2-(2,2′-bipyrid-6-yl)-1,3,4oxadiazo-5-yl]benzene), BPhen(4,7-diphenyl-1,10-phenanthroline), TAZ(3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), PADN(2-phenyl-9,10-di(naphth-2-yl)anthracene), Bpy-FOXD(2,7-bis[2-(2,2′-bipyrid-6-yl)-1,3,4-oxadiazol-5-yl]-9,9-dimethylfluorene),OXD-7 (1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene),HNBphen (2-(naphth-2-yl)-4,7-diphenyl-1,10-phenanthroline), NBphen(2,9-bis(naphth-2-yl)-4,7-diphenyl-1,10-phenanthroline), 3TPYMB(tris(2,4,6-trimethyl-3-(pyrid-3-yl)phenyl)borane), 2-NPIP(1-methyl-2-(4-(naphth-2-yl)phenyl)-1H-imidazo[4,5-f]-[1,10]phenanthroline),Liq (8-hydroxyquinolinolatolithium), and Alq(bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum), and also ofmixtures of the aforesaid substances.

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

A charge transport layer can be doped with conductivity dopants tosubstantially alter its density of charge carriers, which will in turnalter its conductivity. The conductivity is increased by generatingcharge carriers in the matrix material, and depending on the type ofdopant, a change in the Fermi level of the semiconductor may also beachieved. Hole-transporting layer can be doped by p-type conductivitydopants and n-type conductivity dopants are used in theelectron-transporting layer.

Non-limiting examples of the conductivity dopants that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:EP01617493, EP01968131, EP2020694, EP2684932, US20050139810,US20070160905, US20090167167, US2010288362, WO06081780, WO2009003455,WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804,US20150123047, and US2012146012.

A hole injecting/transporting material is not particularly limited, andany compound may be used as long as the compound is typically used as ahole injecting/transporting material. Examples of the material include,but are not limited to: a phthalocyanine or porphyrin derivative; anaromatic amine derivative; an indolocarbazole derivative; a polymercontaining fluorohydrocarbon; a polymer with conductivity dopants; aconducting polymer, such as PEDOT/PSS; a self-assembly monomer derivedfrom compounds such as phosphonic acid and silane derivatives; a metaloxide derivative, such as MoO_(x); a p-type semiconducting organiccompound, such as 1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; ametal complex, and a cross-linkable compounds.

An electron blocking layer (EBL) may be used to reduce the number ofelectrons and/or excitons that leave the emissive layer. The presence ofsuch a blocking layer in a device may result in substantially higherefficiencies, and/or longer lifetime, as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the EBLmaterial has a higher LUMO (closer to the vacuum level) and/or highertriplet energy than the emitter closest to the EBL interface. In someembodiments, the EBL material has a higher LUMO (closer to the vacuumlevel) and/or higher triplet energy than one or more of the hostsclosest to the EBL interface. In one aspect, the compound used in EBLcontains the same molecule or the same functional groups used as one ofthe hosts described below.

The light emitting layer of the organic EL device preferably contains atleast a metal complex as light emitting material, and may contain a hostmaterial using the metal complex as a dopant material. Examples of thehost material are not particularly limited, and any metal complexes ororganic compounds may be used as long as the triplet energy of the hostis larger than that of the dopant. Any host material may be used withany dopant so long as the triplet criteria is satisfied.

One or more additional emitter dopants may be used in conjunction withthe compound of the present disclosure. Examples of the additionalemitter dopants are not particularly limited, and any compounds may beused as long as the compounds are typically used as emitter materials.Examples of suitable emitter materials include, but are not limited to,compounds which can produce emissions via phosphorescence, fluorescence,thermally activated delayed fluorescence, i.e., TADF (also referred toas E-type delayed fluorescence), triplet-triplet annihilation, orcombinations of these processes.

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies and/or longer lifetime as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the HBLmaterial has a lower HOMO (further from the vacuum level) and/or highertriplet energy than the emitter closest to the HBL interface. In someembodiments, the HBL material has a lower HOMO (further from the vacuumlevel) and/or higher triplet energy than one or more of the hostsclosest to the HBL interface.

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In tandem or stacked OLEDs, the CGL plays an essential role in theperformance, which is composed of an n-doped layer and a p-doped layerfor injection of electrons and holes, respectively. Electrons and holesare supplied from the CGL and electrodes. The consumed electrons andholes in the CGL are refilled by the electrons and holes injected fromthe cathode and anode, respectively; then, the bipolar currents reach asteady state gradually. Typical CGL materials include n and pconductivity dopants used in the transport layers.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. may be undeuterated, partially deuterated, andfully deuterated versions thereof. Similarly, classes of substituentssuch as, without limitation, alkyl, aryl, cycloalkyl, heteroaryl, etc.also may be undeuterated, partially deuterated, and fully deuteratedversions thereof.

In yet another aspect of the present disclosure, a formulation thatcomprises the novel compound disclosed herein is described. Theformulation can include one or more components selected from the groupconsisting of a solvent, a host, a hole injection material, holetransport material, and an electron transport layer material, disclosedherein.

Experimental Examples

The following experimental examples are provided for purposes ofillustration only, and are not intended to be limiting unless otherwisespecified. Thus, the disclosure should in no way be construed as beinglimited to the following examples, but rather, should be construed toencompass any and all variations which become evident as a result of theteaching provided herein.

Without further description, it is believed that one of ordinary skillin the art can, using the preceding description and the followingillustrative examples, make and utilize the composite materialsdisclosed herein and practice the claimed methods. The following workingexamples therefore, specifically point out the preferred embodiments ofthe present disclosure, and are not to be construed as limiting in anyway the remainder of the disclosure.

Materials and Methods

Example 1

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 2

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Synthesis of 6-(tert-butyl)-11-methoxyimidazo[1,2-f]phenanthridine

2-(3-methoxyphenyl)-1H-imidazole (1.0 g, 5.74 mmol, 1.0 eq),1,2-dibromo-4-(tert-butyl)benzene (2.18 g, 7.46 mmol, 1.3 eq), Pd(PPh₃)₄(0.66 g, 0.57 mmol, 0.1 eq). Xantphos (0.33 g, 0.57 mmol, 0.1 eq), andK₂CO₃ (2.38 g. 17.22 mmol, 3.0 eq) were added to a dry flask equippedwith a magnetic stir bar. The flask was evacuated and backfilled withnitrogen for three times and DMF (30 mL) was added under the protectionof nitrogen, the reaction mixture was stirred at 140° C. under nitrogenatmosphere overnight. After cooling to room temperature, the mixture waspoured into water, extracted with ethyl acetate. The combined organiclayer was dried with anhydrous Na₂SO₄, filtered and concentrated underreduced pressure. The residue was purified by column chromatography onsilica gel to afford the desired product (0.68 g, 36%).

Synthesis of 6-(tert-butyl)imidazo[1,2-f]phenanthridin-11-ol

6-(tert-butyl)-11-methoxyimidazo[1,2-f]phenanthridine (0.68 g, 2.23mmol), 8 mL of HBr, and 24 mL of HOAc were added to a round bottomflask. The reaction mixture was stirred at 130° C. under nitrogenatmosphere for 2 days. The mixture was neutralized with K₂CO₃ aqueoussolution to pH value of 6. Then the precipitate was filtered off andwashed with water for several times. The collected solid was dried inair under reduced pressure to afford the product as an off-white solid(0.62 g, 92%).

Synthesis of Ligand:

A mixture of 6-(tert-butyl)imidazo[1,2-f]phenanthridin-11-ol (0.4 g,1.38 mmol, 1.0 eq), 11-bromobenzo[c]imidazo[1,2-a][1,5]naphthyridine(0.49 g, 1.65 mmol, 1.2 eq), CuI (0.053 g, 0.276 mmol, 0.2 eq),2-picolinic acid (0.034 g, 0.276 mmol, 0.2 eq), K₃PO₄ (0.59 g, 2.76mmol, 2.0 eq), and 15 mL of DMSO was stirred at 90° C. for 2 days undera nitrogen atmosphere, then cooled down to ambient temperature. Themixture was concentrated under reduced pressure. The residue waspurified through column chromatography on silica gel using hexane/ethylacetate as eluent to obtain the desired ligand as white solid (0.50 g,71%).

Synthesis of Pt (II) Complex:

A mixture of ligand (0.05 g, 0.1 mmol, 1.0 eq), K₂PtCl₄ (0.043 g, 0.105mmol, 1.05 eq), ^(n)Bu₄Br (0.003 g, 0.01 mmol, 0.1 eq), and 7 mL of2-ethoxyethanol was stirred under reflux for 3 days via nitrogenatmosphere protection, then cooled down to ambient temperature. Themixture was concentrated under reduced pressure. The residue waspurified through column chromatography on silica gel usinghexane/methylene chloride as eluent to obtain the desired platinumcompound as white solid (0.01 g, 14%).

Example 3

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 4

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 5

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 6

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 7

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Synthesis of Ligand:

A mixture of 6-mesitylimidazo[1,2-f]phenanthridin-11-ol (0.2 g, 0.567mmol, 1.0 eq), 11-bromobenzo[c]imidazo[1,2-a][1,5]naphthyridine (0.19 g,0.62 mmol, 1.1 eq), CuI (0.022 g, 0.113 mmol, 0.2 eq), 2-picolinic acid(0.014 g, 0.113 mmol, 0.2 eq), K₃PO₄ (0.24 g, 1.13 mmol, 2.0 eq), and 7mL of DMSO was stirred at 90° C. for 2 days under a nitrogen atmosphere,then cooled down to ambient temperature. The mixture was concentratedunder reduced pressure. The residue was purified through columnchromatography on silica gel using hexane/ethyl acetate as eluent toobtain the desired ligand as white solid (0.22 g, 65%).

Synthesis of Pt (II) Complex:

A mixture of ligand (0.057 g, 0.1 mmol, 1.0 eq), K₂PtCl₄ (0.043 g, 0.105mmol, 1.05 eq), ^(n)Bu₄Br (0.003 g, 0.01 mmol, 0.1 eq), and 7 mL of2-ethoxyethanol was stirred under reflux for 3 days via nitrogenatmosphere protection, then cooled down to ambient temperature. Themixture was concentrated under reduced pressure. The residue waspurified through column chromatography on silica gel usinghexane/methylene chloride as eluent to obtain the desired platinumcompound as a white solid (0.012 g, 16%).

Example 8

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 9

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 10

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 11

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 12

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 13

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 14

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 15

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 16

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 17

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 18

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 19

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 20

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 21

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 22

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 23

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 24

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 25

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 26

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 27

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 28

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 29

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 30

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 31

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 32

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 33

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 34

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 35

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 36

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 37

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 38

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 39

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 40

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 41

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 42

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Example 43

In one embodiment, an exemplary compound may be prepared according tothe following scheme:

Synthesis of Ligand:

A mixture of 7-phenylimidazo[1,2-f]phenanthridin-11-ol (0.46 g, 1.48mmol, 1.0 eq), 2-bromo-9-(pyridin-2-yl)-9H-carbazole (0.57 g, 1.78 mmol,1.2 eq), CuI (0.057 g, 0.3 mmol. 0.2 eq), 2-picolinic acid (0.036 g. 0.3mmol. 0.2 eq), K₃PO₄ (0.63 g, 2.96 mmol, 2.0 eq), and 15 mL of DMSO wasstirred at 90° C. for 2 days under a nitrogen atmosphere, then cooleddown to ambient temperature. The mixture was concentrated under reducedpressure. The residue was purified through column chromatography onsilica gel using hexane/ethyl acetate as eluent to obtain the desiredligand as white solid (0.54 g, 66%).

Synthesis of Pt (II) Complex:

A mixture of ligand (0.08 g, 0.14 mmol, 1.0 eq), K₂PtCl₄ (0.066 g, 0.16mmol, 1.1 eq), ^(n)Bu₄Br (0.005 g, 0.014 mmol, 0.1 eq), and 9 mL ofacetic acid was stirred under reflux for 3 days via nitrogen atmosphereprotection, then cooled down to ambient temperature. The mixture wasconcentrated under reduced pressure. The residue was purified throughcolumn chromatography on silica gel using hexane/methylene chloride aseluent to obtain the desired platinum compound as a white solid (0.4 g,40%).

Example 44

In one embodiment, a comparative compound may be prepared according tothe following scheme:

Synthesis of Ligand:

A mixture of imidazo[1,2-f]phenanthridin-11-ol (0.23 g, 1.0 mmol, 1.0eq), 11-bromoimidazo[1,2-f]phenanthridine (0.35 g, 1.2 mmol, 1.2 eq),CuI (0.038 g, 0.2 mmol, 0.2 eq), 2-picolinic acid (0.025 g, 0.2 mmol,0.2 eq), K₃PO₄ (0.42 g, 2.0 mmol, 2.0 eq), and 10 mL of DMSO was stirredat 90° C. for 2 days under a nitrogen atmosphere, then cooled down toambient temperature. The mixture was concentrated under reducedpressure. The residue was purified through column chromatography onsilica gel using hexane/ethyl acetate as eluent to obtain the desiredligand as a white solid (0.31 g, 68%).

Synthesis of Pt (II) Complex:

A mixture of ligand (0.045 g, 0.1 mmol, 1.0 eq), K₂PtCl₄ (0.046 g, 0.11mmol, 1.1 eq), ^(n)Bu₄Br (0.003 g, 0.01 mmol, 0.1 eq), and 9 mL of2-ethoxyethanol was stirred under reflux for 3 days via nitrogenatmosphere protection, then cooled down to ambient temperature. Themixture was concentrated under reduced pressure. The residue waspurified through column chromatography on silica gel usinghexane/methylene chloride as eluent to obtain the desired platinumcompound as a white solid (0.01 g, 12%).

The emission spectrum of an exemplary compound, PtON2-PP4, is presentedin FIG. 2.

The emission spectrum of a second exemplary compound, Pt202-PPy5-tb3, ispresented in FIG. 3.

The emission spectrum of a third exemplary compound, Pt202-P2-M3, atroom temperature and at 77 K, is presented in FIG. 4.

DFT modeling of Pt202-P2 and Pt202-P2-M3 (FIG. 5) show the departurefrom planar geometry caused by the mesitylene substituent.

The disclosures of each and every patent, patent application, andpublication cited herein are hereby incorporated herein by reference intheir entirety. While this disclosure refers to specific embodiments, itis apparent that other embodiments and variations of this disclosure maybe devised by others skilled in the art without departing from the truespirit and scope of the disclosure. The appended claims are intended tobe construed to include all such embodiments and equivalent variations.

We claim:
 1. A compound of General formula I, General formula II,General formula III, or General formula IV;

wherein, in General formula I to IV, Y^(2a), Y^(2b), Y^(2c), Y^(2d),Y^(4a), Y^(4b), Y^(4c), Y^(5a), Y^(5b), Y^(6a), Y^(6b), Y^(6c), and X²each independently represent C or N; X, X¹, V¹, and V² eachindependently represent no bond, O, S, Se, NR⁷, PR⁷, AsR⁷, SbR⁷, BiR⁷,R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸, GeR⁷R⁸, C═O, SO₂, orSeO₂; each occurrence of R² independently represents substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof; each of R¹,R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent or present as a singlesubstituent or multiple substituents, valency permitting, and each of R,R¹, R³, R⁴, R⁵, R⁶, R⁷, and R⁸ independently represents deuterium,halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl,mercapto, sulfo, carboxyl, hydrazino; substituted or unsubstituted:aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl,alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino,diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl,acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino,sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl,polymeric; or any conjugate or combination thereof; each n isindependently an integer, valency permitting; and L⁴, L⁵, and L⁶ eachindependently represents a 5- to 10-membered aryl, heteroaryl, fusedaryl, or fused heteroaryl.
 2. The compound of claim 1, wherein thecompound of General formula I, General formula II, General formula III,or General formula IV is a compound of General formula V, Generalformula VI, General formula VII, or General formula VIII;

wherein, in General formula V to VIII; Y^(2a), Y^(2b), Y^(2c), Y^(2d),Y^(4a), Y^(4b), Y^(4c), Y^(4d) and X² each independently represents C orN; each of X and X¹ independently represents no bond, O, S, Se, NR⁷,PR⁷, AsR⁷, SbR⁷, BiR⁷, R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸,GeR⁷R⁸, C═O, SO₂, or SeO₂; each occurrence of R² independentlyrepresents substituted or unsubstituted: aryl, cycloalkyl, cycloalkenyl,heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino,monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy,aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino,alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl,carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or anyconjugate or combination thereof; each of R, R¹, R³, R⁴, R⁵, R⁶, R⁷ andR⁸ is independently absent or present as a single substituent ormultiple substituents, valency permitting, and each of R, R¹, R³, R⁴,R⁵, R⁶, R⁷ and R⁸ independently represents deuterium, halogen, hydroxyl,thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo,carboxyl, hydrazino; substituted or unsubstituted: aryl, cycloalkyl,cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino,monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy,aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino,alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl,carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric; or anyconjugate or combination thereof; and each n is independently aninteger, valency permitting.
 3. The compound of claim 1, wherein thecompound has a neutral charge.
 4. The compound of claim 1, wherein X andX¹ are present and each independently represent O, NR⁷, CR⁷R⁸, orSiR⁷R⁸.
 5. The compound of claim 1, wherein X² represents N.
 6. Thecompound of claim 2, wherein at least one of Y^(2a), Y^(2b), Y^(2c),Y^(2d), Y^(4a), Y^(4b), Y^(4c), and Y^(4d) represents N.
 7. The compoundof claim 2, wherein only one of Y^(2a), Y^(2b), Y^(2c), Y^(2d), Y^(4a),Y^(4b), Y^(4c), and Y^(4d) represents N and the remaining of Y^(2a),Y^(2b), Y^(2c), Y^(2d), Y^(4a), Y^(4b), Y^(4c), and Y^(4d) represent C.8. The compound of claim 1, wherein L⁶ is 5- to 10-membered heteroarylor fused heteroaryl.
 9. The compound of claim 1, wherein L⁶ isimidazole, benzimidazole, or pyridine.
 10. The compound of claim 1,wherein at least one of V¹ and V² represents no bond.
 11. The compoundof claim 1, wherein each occurrence of R² is independently selected fromthe group consisting of substituted or unsubstituted alkyl, substitutedor unsubstituted aryl, or combinations thereof.
 12. The compound ofclaim 1, wherein at least one occurrence of R⁵ is selected from thegroup consisting of substituted or unsubstituted alkyl, substituted orunsubstituted aryl, or combinations thereof.
 13. The compound of claim1, wherein each occurrence of R² is independently selected from thegroup consisting of


14. The compound of claim 1, wherein each occurrence of R¹, R³, R⁴, R⁵,R⁶, R⁷, and R⁸ is independently selected from the group consisting of:

wherein each of R independently represents hydrogen, deuterium, halogen,hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto,sulfo, carboxyl, hydrazino; substituted or unsubstituted: aryl,cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl,alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino,diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl,acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino,sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl,polymeric; or any conjugate or combination thereof.
 15. The compound ofclaim 1, wherein the compound is selected from the group consisting of:


16. An organic light emitting device (OLED) comprising: an anode; acathode; and an organic layer disposed between the anode and thecathode; wherein the organic layer comprises a compound of Generalformula I, General formula II, General formula III, or General formulaIV;

wherein, in General formula I to IV, Y^(2a), Y^(2b), Y^(2c), Y^(2d),Y^(4a), Y^(4b), Y^(4c), Y^(5a), Y^(5b), Y^(6a), Y^(6b), Y^(6c), and X²each independently represent C or N; X, X¹, V¹, and V² eachindependently represent no bond, O, S, Se, NR⁷, PR⁷, AsR⁷, SbR⁷, BiR⁷,R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸, GeR⁷R⁸, C═O, SO₂, orSeO₂; each occurrence of R² independently represents substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof; each of R,R¹, R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent or present as asingle substituent or multiple substituents, valency permitting, andeach of R, R¹, R³, R⁴, R⁵, R⁶, R⁷, and R⁸ independently representsdeuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile,sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof; each n isindependently an integer, valency permitting; and L⁴, L⁵, and L⁶ eachindependently represents a 5- to 10-membered aryl, heteroaryl, fusedaryl, or fused heteroaryl.
 17. The device of claim 16, wherein theorganic layer further comprises a host.
 18. The device of claim 17,wherein the host comprises at least one selected from the groupconsisting of a metal complex, triphenylene, carbazole,dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-triphenylene,aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, andaza-dibenzoselenophene.
 19. A consumer product comprising the device ofclaim 16, wherein the consumer product is selected from the listconsisting of a flat panel display, a computer monitor, a medicalmonitor, a television, a billboard, a light for interior or exteriorillumination and/or signaling, a heads-up display, a fully or partiallytransparent display, a flexible display, a laser printer, a telephone, acell phone, tablet, a phablet, a personal digital assistant (PDA), awearable device, a laptop computer, a digital camera, a camcorder, aviewfinder, a micro-display that is less than 2 inches diagonal, a 3-Ddisplay, a virtual reality or augmented reality display, a vehicle, avideo wall comprising multiple displays tiled together, a theater orstadium screen, and a sign.
 20. A formulation comprising a compound ofGeneral formula I, General formula II, General formula III, or Generalformula IV;

wherein, in General formula I to IV, Y^(2a), Y^(2b), Y^(2c), Y^(2d),Y^(4a), Y^(4b), Y^(4c), Y^(5a), Y^(5b), Y^(6a), Y^(6b), Y^(6c), and X²each independently represent C or N; X, X¹, V¹, and V² eachindependently represent no bond, O, S, Se, NR⁷, PR⁷, AsR⁷, SbR⁷, BiR⁷,R⁷P═O, R⁷As═O, R⁷Bi═O, BR⁷, AlR⁷, CR⁷R⁸, SiR⁷R⁸, GeR⁷R⁸, C═O, SO₂, orSeO₂; each occurrence of R² independently represents substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof; each of R,R¹, R³, R⁴, R⁵, R⁶, R⁷ and R⁸ is independently absent or present as asingle substituent or multiple substituents, valency permitting, andeach of R, R¹, R³, R⁴, R⁵, R⁶, R⁷, and R⁸ independently representsdeuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile,sulfinyl, mercapto, sulfo, carboxyl, hydrazino; substituted orunsubstituted: aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl,alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino,monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester,alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino,sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide,silyl, polymeric; or any conjugate or combination thereof; each n isindependently an integer, valency permitting; and L⁴, L⁵, and L⁶ eachindependently represents a 5- to 10-membered aryl, heteroaryl, fusedaryl, or fused heteroaryl.